Metal cutting tools of the kind to which the present invention relates and which are designed for use in cutting, parting, grooving, turning, and facing operations and the like, generally consist of holder blades of relatively narrow transverse dimensions having formed at one end thereof an open-ended insert pocket within which replaceable cutting inserts are located and retained, they themselves being in their turn held in appropriate tool blocks designed to be secured to the machine tools. The effective retention of the inserts in the insert pockets in such a manner than they are securely held during cutting but can nevertheless be readily released when replacement is called for, has exercised the minds of the designers of such cutting tools for some considerable time.
Thus, in accordance with one type of solution proposed and used to this end, the insert is clamped in position within the insert pocket by the spring biasing force exerted thereon by a resiliently distorted portion of the holder blade itself.
In accordance with another set of proposals directed to the problem of the effective retention of the insert within the insert pocket, the holder blade is provided with separate and manually actuatable mechanical means for mechanically clamping the insert within the insert pocket.
In accordance with one particular proposal falling into this second category (U.S. Pat. No. 4,357,123--Zweekly) the holder blade is formed with an elongated slot which extends from a longitudinal edge of the blade to a region an inner end of the insert pocket, the slot being formed with a central widened portion designed to receive a camming member which, upon rotation, causes an inwardly directed displacement of the opposite faces of the insert pocket, the effective clamping within the insert pocket of a cutting insert located therein.
The use of such rotatable camming elements so as to secure the clamping displacement of the bounding surfaces of the insert pocket has been previously proposed, for example in DE 3301919 (Keller); DOS 2742423 (Heinlein) and DOS 226472 (Ugine-Carbone). It will be appreciated, however, that the rotation of such a camming element gives rise to forces which are not necessarily limited in their direction to that of the displacement of the bounding surfaces of the insert pocket. Thus, the effort exerted in rotating the camming element is not always most efficiently utilized for achieving the desired displacement of these bounding surfaces.